Thanks in advance for any help ya'll can provide. I aquired a 743 last week from an individual. At the time of purchase the machine was working well. However, after running it for around 30 minutes it began to make a horrible gear grinding sound that seems to come from the area where the engine connects to the pump. I immediately shut the motor down and pulled the machine into the shop. I then allowed the machine to cool down for 24 hours. During this time I changed the hydraulic filter located in the engine compartment. After the cool down period, I restarted the machine briefly. The grinding noise was not as bad while the engine was cold but got progressively worse as things warmed up. The lift arms, wheels and bucket still works though noticably sluggish. I am not familiar with the how power is transmitted from the engine to the pump ie spline drive, belts etc... Was wondering if others may have seen this problem before. Again, I appreciate any and all info....